TfOH-promoted multichannel transformations of trifluoromethyl side chain substituted thiophene and furan families to access antimicrobial agents

Trimethylsilyl ethers of trifluoromethyl substituted benzyl type alcohols of thiophene and (benzo)furan series undergo multichannel electrophilic transformations in triflic acid CF3SO3H (TfOH). Intermediate cationic species generated from starting heterocycles interact with arenes, leading to the formation of various products of side chain arylation, dehalogenation, arylation of the heteroaromatic core, intramolecular cyclization, hydro-detrimethylsilylogenation, oxo-dehalogenation, and others. The reaction pathway depends on the structure of an intermediate cation, nucleophilicity of the arene, reaction time, and temperature. Plausible mechanisms of these electrophilic reactions are discussed. The obtained trifluoromethyl substituted compounds exhibit good antimicrobial activity against Candida albicans, a yeast-like fungus, at concentrations ranging from 64 to 128 mu g mL-1 and inhibit the growth of both Escherichia coli and Staphylococcus aureus. TMS-ethers of the CF3-benzyl type alcohols of the thiophene and (benzo)furan series undergo transformations in TfOH, leading to the formation of various products of side chain arylation, dehalogenation, arylation of the heteroaromatic core, and others.